The present invention relates to a data transmission circuit and system for use in hazardous or nonhazardous environments. In the preferred embodiment, the system is a bi-directional, low energy, current loop data communication circuit primarily for high speed data communications via parallel or twisted pair conductors. In the preferred embodiment, the system of the present invention can safely transmit data across distances up to 1000 feet (300 meters) in an explosive atmosphere. The circuit preferably allows multiple communication circuits to be contained within a single cable without crosstalk interference. Further protections can be provided by optically isolating a portion of the circuit for use in the hazardous area with the circuit for use in the safe area.
The present invention provides a safe communication circuit that can be used in a hazardous environment, e.g., one with fuel that is conducive to an explosive atmosphere. Traditionally, data communication circuits intended to transmit information at high speeds and across long distances required energy levels that may be unsafe for use in a hazardous environment. Accordingly, the present invention advances the state of the art by providing a novel method and system for communicating data at lower, safer, energy levels while maintaining the ability to transmit data across long distances at high speeds.